It must be a conspiracy. Perhaps engineers working for the banned religious group Falun Gong hacked into the computer system of the Shanghai Composite Index.
How else could you explain that on the most politically charged date of the year - June 4 - the index tumbled exactly 64.89 points? That's not the only coincidence. The market opened at 2,346.98 points; Monday marked the 23rd anniversary of the brutal crackdown, and 46.98 is the date read backwards.
Some people joked in the Chinese blogosphere that mainland censors would have to shut down the stock market and block discussion of it. Well, that turned out to be no joke. The index stayed open but 'Shanghai Composite Index' has been added to a list of sensitive words and phrases blocked on mainland microblog searches. But that didn't stop people discussing it.
Thanks to heavy-handed censorship, what started off as small discussions in chat rooms went on to become big news in the world press. That should teach mainland authorities a lesson. When a topic becomes taboo, it does not disappear.
It has a way of sneaking past censors via coded messages, such as the clever use of images, words and phrases. It may be true many young people on the mainland today know little about June 4. But their ignorance is not due to a general lack of interest in history and current affairs; it is due to the effect of censorship.
It is unrealistic to expect the mainland to allow the kind of free media and expression enjoyed in Hong Kong and Western democracies. But it would further the soft power and influence of the central government if censorship were exercised more cleverly.
Loosening its grip a bit may actually help improve Beijing's image and credibility at home and abroad.
Generally, intelligent discussions are better than suppression. In any case, it is doubtful that China, however wealthy and powerful, will ever become a 'normal country' until its citizens can openly discuss this terrible episode in our history.
This is an edited version of an article by Alex Lo, which appeared in the SCMP on June 6
Following Mao's thoughts
China expert Jerome A Cohen is professor and co-director of the US-Asia Law Institute at New York University's School of Law.
He sees a lot of similarities in the way Beijing handled the June 4 uprising and the spiritual group, Falun Gong. He says the government follows Mao Zedong's maxim that 'A single spark can start a prairie fire'. Under that policy, the authorities don't tolerate open dissent and snuff out its sparks.
Led by Deng Xiaoping , the Communist Party wasted no time sending troops against students in Tiananmen Square on June 4, 1989. A decade later, Deng's successor Jiang Zemin applied the 'lesson of Tiananmen' by suppressing the Falun Gong movement after some 10,000 of its supporters staged a public rally.
Mao died in 1976, but his influence has remained strong on the mainland. Some China-watchers, however, insist that Maoism lost its ability long ago to influence official policy. Today it serves mainly to project an image of unbroken communist continuity amid profound national transformations.
Yet it is undeniable that criminal justice is one prominent area where Mao's thinking has left an indelible impact. Foreign observers, as well as the country's legal scholars, daily encounter cases where 'politics takes command' over law - not only among police and prosecutors but also among judges. Such politicisation of criminal justice follows the public instructions of Beijing's highest-ranking leaders.
In tense times, even law professors have had to accommodate the chairman's views, as Cohen discovered.
In February 1992, the Voice of America broadcast excerpts of a talk by Cohen at the Beijing Foreign Correspondents' Club. He argued that mainland courts were instruments of suppression.
When he returned to his hotel, he found five Beijing law school deans waiting for him 'to register a solemn protest' about his views.
He said they asked him how 'a friend of China' could make such a claim. Cohen told them he had merely been quoting speeches by Ren Jianxin, then president of the Supreme People's Court and head of the party's Political and Legal Affairs Commission, who spoke in the months after the 1989 Tiananmen crackdown.
'Oh,' Cohen quoted them responding, 'Ren was only telling the courts to suppress counter-revolutionaries, not the 'people'!'
'As long as Mao's pernicious doctrine persists, no Chinese citizen can be safe,' Cohen insisted.
The powerful Party
Since 1989, many scholars and politicians in the West have confidently predicted the collapse of the Chinese Communist Party (CCP). They said that economic reform would inevitably lead to political reform and that one was impossible without the other. But they have been proved very wrong. The government today has more than US$3 trillion in foreign exchange reserves. It also has the largest military in East Asia and has an internal security system that is far more potent than that of ousted Egyptian president Hosni Mubarak or ex-Tunisian strongman Zine el Abidine Ben Ali.
Mao's Invisible Hand, a book edited by China specialists at Germany's Trier and America's Harvard universities, examines how the CCP has managed to hold on to power while delivering three decades of economic growth.
The book says Beijing has avoided the mistakes of the Soviet and eastern European communist parties, in which bureaucratic conservatism and entrenched interests blocked reforms. Instead, Beijing has been willing to adapt and experiment economically, if not politically.
But blind human rights activist Chen Guangcheng disagrees. He says the mainland's outdated social system is withering away. 'The government is terrified and has 'a sense of crisis'. It is afraid people will learn of its misconduct, which is why it goes to such extremes to hide its actions and isolate [officials from scrutiny]. If a society is not built on the foundation of fairness and justice, it will not gain long-lasting stability,' he said.
'Violence will only maintain short-term stability.'
'Around 30,000 people are employed in a 'gigantic apparatus of monitoring and censorship'. A month-long investigation found that the authorities used a system of filters to screen content on the Falun Gong, Taiwanese moves towards independence, the anniversary of the Tiananmen Square crackdown, and human rights issues.'
Reporters Without Borders
'With internet call-in, we have the ability to choose which question goes on air and which doesn't. We can't go [on air] ... We don't want someone calling in with a June 4 question or a Falun Gong question. That may be fine in Hong Kong, but it's not fine on the mainland.'
Liu Changle, chairman and CEO of Hong Kong-based Phoenix TV, about the TV station's 2003 plan to broadcast live debates held between viewers and commentators
'Freedom of religion and freedom of belief are common values of a free society. People are pained to see the mainland's persecution and killing of students of the Falun Gong. There can't be any hope for reunification unless Beijing changes its attitude.'
Taiwanese President Ma Ying-jeou, speaking about the mainland's crackdown on the Falun Gong movement in 2005
Timeline of Chinese Communist Party's crackdown on Falun Gong movement
1992: Falun Gong founder Li Hongzhi begins publicising his beliefs on the mainland.
1996: Falun Gong books are banned from further publication by the China News Publishing Bureau for 'spreading superstition'.
1998: The Ministry of Public Security issues a document that asserts Falun Gong is an 'evil religion'.
April 25, 1999: Some 10,000 members of the semi-religious sect surround the Zhongnanhai compound in Beijing, home to senior leaders.
June 26, 1999: Thirteen Falun Gong exercise sites in public parks are shut down by Beijing security officials.
July, 1999: A nationwide suppression campaign is rolled out to 'eradicate' Falun Gong. The campaign includes sending tens of thousands of Falun Gong members to prison or to labour camps to be re-educated.
2001: For the first time, authorities openly sanction the 'systematic use of violence' against the group. They establish a network of propaganda classes to root out Falun Gong practitioners 'neighbourhood by neighbourhood and workplace by workplace'.
February 14, 2002: Falun Gong supporters from overseas attempt to stage a demonstration in Tiananmen Square. They are detained, and several are assaulted by security forces and then expelled from China.
2007: Falun Gong sources report that the number of violent deaths among members exceeds 3,000.
2008: More than 8,000 Falun Gong followers are abducted by security forces under the pretext of preventing protests during the Beijing Olympics.
2009: Human rights lawyers who seek to represent Falun Gong defendants continue to face punishment from mainland authorities. Among other things, they faced harassment, dismissal and imprisonment.
2010: Mainland authorities launch a new campaign whose goal is to forcefully transform large groups of the known Falun Gong population through compulsory attendance at re-education classes.